CONSOLIDATED STATEMENTS OF OPERATIONS - USD ($) shares in Thousands, $ in Thousands	12 Months Ended
	Dec. 31, 2016	Dec. 31, 2015	Dec. 31, 2014
Income Statement [Abstract]
Net sales	$ 566,852	$ 524,505	$ 535,829
Cost of sales	428,310	402,008	420,851
Gross profit	138,542	122,497	114,978
Selling, product development and administrative expenses	83,750	70,020	80,930
Operating income	54,792	52,477	34,048
Gain on sale of business	0	(18,647)	0
Interest expense	1,068	755	1,093
Other income, net	(1,215)	(654)	(701)
Income before income taxes	54,939	71,023	33,656
Income tax expense	17,821	24,764	11,809
Income from equity method investment	(69)	0	0
Net income	$ 37,187	$ 46,259	$ 21,847
Earnings per common share:
Basic (in dollars per share)	$ 2.20	$ 2.76	$ 1.31
Diluted (in dollars per share)	$ 2.16	$ 2.71	$ 1.28
Weighted average common shares outstanding (in shares)	16,871	16,746	16,662
Weighted average common shares and equivalents outstanding (in shares)	17,241	17,084	17,003